Direct patterning of spin-on glass with 157nm lithography: Application to nanoscale crystal growth

Bloomstein, Theodore M.; Juodawlkis, Paul W.; Swint, R.B.; Cann, Susan G.; Deneault, S. J.; Efremow, N. N.; Hardy, D. E.; Marchant, Michael; Napoleone, A.; Oakley, D.C.; Rothschild, M.

doi:10.1116/1.2101692

Cited by 12 publications

(3 citation statements)

References 13 publications

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“…The development mechanism of HSQ has been considered to consist of two main competing processes of dissolution and cross-linking. 14 We believe that the effect of the salt was to change the relative rates of dissolution and crosslinking by affecting the mean chemical activity of the ionic species present in the solution. For instance, a larger difference between dissolution and cross-linking rates can be seen as an explanation for increased contrast.…”

Section: Figmentioning

confidence: 99%

Using high-contrast salty development of hydrogen silsesquioxane for sub-10-nm half-pitch lithography

Yang

Berggren²

2007

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

181

154

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When used as a negative-tone electron-beam resist, hydrogen silsesquioxane (HSQ) is typically developed in an aqueous alkali solution such as tetramethyl ammonium hydroxide. This development process results in low contrast. In this work, the authors instead used a mixture of salt and alkali to significantly increase the contrast of HSQ. Contrast values as high as 10 in a 115-nm-thick resist were achieved by developing HSQ in an aqueous mixture of NaOH alkali and NaCl salt. Remarkably, this salty developer resulted in contrast enhancement without significant decrease in resist sensitivity. The improved contrast of HSQ enabled the fabrication of 7nm half-pitch nested-“L” structures in a 35-nm-thick resist with minimal loss in thickness using a 30kV electron-beam acceleration voltage. They noticed a strong dependence of contrast enhancement on the concentration and type of cations and anions in the aqueous developer solution.

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Section: Figmentioning

confidence: 99%

Using high-contrast salty development of hydrogen silsesquioxane for sub-10-nm half-pitch lithography

Yang

Berggren²

2007

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

181

154

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“…While these challenges have greatly impeded the use of nanopatterning in device fabrication, studies employing in situ etching and regrowth of low-dimensional structures [58] and wet chemical etching with selective MOCVD QD growth [64], have recently shown promising potential for realizing high performance devices. Various methods have been successfully employed to fabricate such semiconductor based nanostructures, including interferometric optical lithography [59][60][61], x-ray lithography [62], atomic force microscopy based lithography [63], electron beam lithography [64][65][66], scanning tunnelling microscopy (STM) [67,68] and self-organized anodic aluminium oxide membranes [69,70]. Among these techniques, electron beam lithography has demonstrated semiconductor nanopatterns with dimensions in the 10-20 nm range [71] as early as the 1980s.…”

Section: Qds Grown By Intentional Patterning-past Literaturementioning

confidence: 99%

Nanofabrication of III–V semiconductors employing diblock copolymer lithography

Kuech¹,

Mawst²

2010

J. Phys. D: Appl. Phys.

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To fully exploit the potential advantages of ideal quantum dots (QDs) (i.e. full 3D carrier confinement), elimination of the wetting layer and a uniform monomodal QD size distribution is needed. Nanopatterning with selective metalorganic chemical vapour deposition (MOCVD) QD growth has potential for achieving a higher degree of control over the QD formation, compared with the conventional Stranski–Krastanov (SK) self-assembly growth process. QD formation employing large surface area patterning prepared by dense nano-scale (20–30 nm diameter) diblock copolymer lithography is described. The resulting pattern consists of perpendicularly ordered cylindrical domain formed as part of a self-organizing diblock copolymer, such as polystyrene-block-poly(methylmethacrylate) (PS-b-PMMA). This pattern can be transferred to an underlying substrate or dielectric layer. Selective MOCVD growth of the QDs is achieved by employing the nanopatterned template mask. The resulting QD densities of 5 × 1010 cm−2 are comparable to densities achieved using the SK self-assembly growth mode. Nanopatterned growth yields a nearly monomodal QD size distribution. Variable temperature photoluminescence has been used to characterize the optical properties of capped InGaAs QDs on GaAs (λ ∼ 1.1 µm) and InP (λ ∼ 1.5 µm) substrates and preliminary results on the incorporation of such materials into diode laser structures are discussed. The extension of nanopatterned growth, beyond the pseudomorphic limit in the case of growth of strained-layer epitaxy, can lead to defect reduction and an improved morphology when compared with non-patterned growth.

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“…Figure 3 is a scanning electron microscope (SEM) image of the patterned HSQ structure after lithography and development. Once written, HSQ breaks down into silicon dioxide, allowing it to be used directly as a mask for selective area growth [6]. …”

mentioning

confidence: 99%

Three-Dimensional Quantization from an Ordered Nanopore Array Diode Laser

Elarde

Coleman

2007

2007 Conference on Lasers and Electro-Optics (CLEO)

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The ordered nanopore array laser diode is a structure which exhibits three-dimensional carrier confinement similar to quantum dot lasers without the undesirable effects of spatially disconnected carrier pools. Simulation and experimental results will be presented. IntroductionQuantum dots, specifically the growth of patterned quantum dots [1], has been heavily studied in recent years due to the potential advantages [2, 3] of full, three-dimensional carrier confinement that these structures achieve. We have previously reported [4, 5] on a process for fabricating explicitly patterned quantum dots using nanoscale electron beam lithography and selective area metal-organic chemical vapor deposition (MOCVD) which allows a greater degree of control over the structure than can be achieved by conventional self-assembly techniques. In this work, we have extended this fabrication process to create an ordered nanopore array active layer which consists of a quantum well containing an in-plane lattice of localized energy barriers with feature sizes on the order of the electron wavelength. This nanopore structure results in a reduction of the electronic density of states within the active layer allowing many of the advantages of quantum dots associated with three-dimensional (3-D) quantization. At the same time, the array of 3-D quantum potential wells created by the nanopore lattice share a common carrier pool, reducing or eliminating the inhomogeneous broadening observed in spatially separated quantum dots.The work presented here is the first reported demonstration of high performance room-temperature nanopore laser diodes. It is an initial proof-of-concept that the density of states, and thus, the absorption/gain spectrum of a quantum well, can be modified through the introduction of a periodic potential barrier, and that the fabrication process is capable of producing high quality devices. Theory of the Nanopore LaserThe nanopore laser consists of a quantum well laser with an active layer which has been periodically perturbed with localized high energy barriers. Figure 1 is an illustration of the nanopore active layer. It resembles an inverted conventional single-layer quantum dot system where the "dots" are high potential energy regions compared to the background. Theoretically, this structure should result in an energy configuration containing a ground state solution corresponding to a wavefunction which is highly localized to the regions between the energy barriers. A forbidden energy band separates it from a continuum band of higher energy states. Figure 2 shows the calculated dispersion relationship for a square lattice ordered nanopore array. The size of the forbidden band and the configuration of the energy states depend on the lattice constant of the structure and the physical size of the barrier regions. The continuum states provide a mechanism for strong electronic coupling and a common carrier pool for the localized states. Fabrication ProcessInitially a base structure is grown that consists of the lower half of ...

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Direct patterning of spin-on glass with 157nm lithography: Application to nanoscale crystal growth

Cited by 12 publications

References 13 publications

Using high-contrast salty development of hydrogen silsesquioxane for sub-10-nm half-pitch lithography

Using high-contrast salty development of hydrogen silsesquioxane for sub-10-nm half-pitch lithography

Nanofabrication of III–V semiconductors employing diblock copolymer lithography

Three-Dimensional Quantization from an Ordered Nanopore Array Diode Laser

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